21st Century Impact of Greenhouse Effects on the Middle and Lower Reaches of the Yangtze River

摘要

Climate changes on the middle and lower reaches of the Yangtze River region due to greenhouse effects in the 21st century are investigated based on the simulations both by coupled atmosphere-ocean general circulation models (AOGCM) and a regional climate model (RegCM2). The AOGCM part is based on the average of the 5 AOGCM results provided by the Data Distribution Center (DDC) of IPCC. It consists of 4 scenarios, which are greenhouse gas only (GG), and a greenhouse gas plus sulfate aerosol (GS) scenario of the IS92a, A2, and B2 of the SRES. The results show a general warming in the region in the future, as there will be across the globe and in the other parts of China. For example, at the end of the 21st century, the warming of 4.2°C under GG and 3.TC under GS in the region are simulated. But the warming is generally smaller than that averaged in China. Greater warming is found in winter and spring than in summer and autumn. As for precipitation change, under GG, an increase smaller than that averaged in China is simulated, while under GS it is a slight decrease. The RegCM2 shows similar warming in the region. But precipitation change is different in viewing the seasonal scale changes. Higher increase is simulated in winter and summer with the value to be 44% and 23% respectively. A decrease of precipitation is found in spring and autumn, which is in the opposite direction as demonstrated by the AOGCM's.